1. Field of the Invention
The invention relates to light valves, and to displays using light valves, including television displays.
2. Description of the Prior Art
It has been suggested that the transmission of light from phase gratings may be used for purposes of display for instance, in making a microfiche or the like or in slide projectors. See, for example, R. Bartolini et al., Applied Optics, Vol. 9 (1970) p. 2283 and M. T. Gale et al., Micrographics, Vol. 8 (1975) p. 225. It has also been suggested that relief diffraction gratings may be used for display purposes.sup.1,2 (numbered references will be found at the end of the specification), and the theory will be discussed briefly hereinafter to the extent desirable for an understanding of the present invention. It is also known that PVF.sub.2 may be made to exhibit a piezoelectric effect.sup.3. The effect and some of its various possible applications are discussed at greater length in an article in Science, "Flexible PVF.sub.2 Film: An Exceptional Polymer for Transducers" Vol. 200, June 23, 1978, pp. 1371-1374.
Display effects using a piezoelectric effect are suggested in U.S. Pat. No. 3,172,221 to Ochs, Jr., Dated Mar. 9, 1965. Displays employing diffraction grating effects are suggested in U.S. Pat. No. 3,861,784 to Torok, dated Jan. 21, 1975; U.S. Pat. No. 3,752,563 to Torok et al., dated Aug. 14, 1973; U.S. Pat. No. 4,082,425 to Miller, dated Apr. 4, 1978; and U.S. Pat. No. 4,011,009 to Lama et al., dated Mar. 8, 1977.
U.S. Pat. No. 3,942,048 to Laude et al., dated Mar. 2, 1976 describes a method for modulating the blaze angle of a diffraction grating by an applied voltage. U.S. Pat. No. 3,347,614 to Fuller dated Oct. 17, 1967 describes a display comprising identical panel elements hermetically scaled and containing magnetic film and colloidal iron suspension and each excited to diffract light to create in total an optical image.
U.S. Pat. No. 3,347,614 to Fuller et al, dated Oct. 17, 1967, describes a display device using diffraction effects associated with a suspension of ferromagnetic particles in a liquid overlying a ferromagnetic film.
U.S. Pat. No. 3,782,806 to Barkley et al, dated Jan. 1, 1974 describes a light switch using polarization filtering and a ferroelastic effect in certain types of crystals to provide an optical switch, and can be used to provide line scanning.
U.S. Pat. No. 3,897,997 to Kalt, dated Aug. 5, 1975, describes a display device using flexible elements electrostatically actuated, and U.S. Pat. No. 1,888,893 to Tschorner, Nov. 22, 1932, suggests a picture reproducing device for television using two superimposed line or cross screens the relative motion of which can expose only the single element at the intersection to light transmission.
Other U.S. patents which may be of interest are U.S. Pat. No. 3,957,354, dated May 18, 1976 to Knop; U.S. Pat. No. 4,057,326, dated Nov. 8, 1977, to Gale; U.S. Pat. No. 4,082,453, dated Apr. 4, 1978, to Knop; and U.S. Pat. No. 4,082,438, dated Apr. 4, 1978, to Knop.